Such a steering arrangement is usually used to steer a vehicle. The steering unit is connected to a steering wheel or another steering command generator. When the steering wheel is turned, it is intended to turn the steered wheels as well.
In order to save energy, a steering unit is often connected to an adjustable pressure source. The output pressure of this pressure source is adapted to the required pressure, i.e. the pressure is increased only when there is a demand. Such a demand arises when the driver intends to steer the vehicle. When there is no steering requirement, the pressure of the pressure source is lowered.
In a static steering unit the pressure demand is signaled to the adjustable pressure source with a certain delay after the start of the turning of the steering wheel. This has the negative effect that the steering of the steered wheels is delayed.